High frequency radio frequency (RF) plasma processes may produce a higher ionization ratio, as compared to other conventional plasma processes (e.g., such as a DC plasma process), thereby providing more flexibility and a wider range of process applications. However, the inventors have observed that, when performing etch processes utilizing a high frequency power source, an etching rate proximate an edge of a substrate may be higher (e.g., such as 2 to 3 times higher or greater) that that of an etching rate in other regions of the substrate, thereby leading to undesirable non-uniform etching results.
Therefore, the inventors have provided an improved method for processing susbstrates.